Questions on UI for WPF Forum

1 answer

191 views

Inconsistent behavior in GridViewDataColumn template binding

I have a column in my RadGridView that displays some text and then also contains a button that should only be visible to users with permission to change the data. I'm using MVVM and the viewmodel exposes a boolean property named UserHasWriteAccess that indicates the user's permission level. The column and its datatemplate are defined as follows.

<telerik:GridViewDataColumn Header="Reason Code">

<telerik:GridViewDataColumn.CellTemplate>

<DataTemplate>

<Grid>

<Grid.ColumnDefinitions>

<ColumnDefinition Width="*" />

<ColumnDefinition Width="Auto" />

</Grid.ColumnDefinitions>

<TextBlock Text="Lorem ipsum" />

<Button Content="Edit"

Height="23"

HorizontalAlignment="Right"

Margin="4,0,0,0"

Visibility="{Binding DataContext.UserHasWriteAccess,

Mode=OneTime,

Converter={StaticResource BooleanToVisibilityConverter},

RelativeSource={RelativeSource AncestorType=telerik:RadGridView}}">

</Grid>

</DataTemplate>

</telerik:GridViewDataColumn.CellTemplate>

</telerik:GridViewDataColumn>

When UserHasWriteAccess is false, the button's visibility binding works fine most of the time (~99%) and the button does not show. However, as the user scrolls up and down through the grid, eventually intermittent binding errors will suddenly appear for a row or two for which the binding worked previously. Sometimes the user has to scroll up and down several times before it happens. Other times it's immediate. The errors say:

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='Telerik.Windows.Controls.RadGridView', AncestorLevel='1''. BindingExpression:Path=DataContext.UserHasWriteAccess; DataItem=null; target element is 'Button' (Name=''); target property is 'Visibility' (type 'Visibility')

Curiously, when I inspect an errored binding using Snoop, it suddenly works again.

Is there a known issue with ancestor binding in RadGridView?

GridView

answered on 18 May 2012

1 answer

368 views

Empty text in NumericUpDown issue

Hello!

We are using MVVM pattern to build our application. One of our views uses number of NumericUpDown controls. If text of some NumericUpDown is set to empty string by user control displays red frame (see screenshot "validation error"). Property definition you can find in screenshot named "amount property".

The problem is that view model is not updated when text is empty and red frame is displayed. E.g. model still contains previous value.

What is correct way to notify View Model about missing data? Keep in mind that we have significant number of views and each contains set of numeric controls.

NumericUpDown

answered on 18 May 2012

0 answers

200 views

WPF RadGrid copy Cell value to clipboard.

We have a WPF app which uses RadGrid. As part of the app functionality, we want the grid selection unit to always be of type "row". In addition to this, we also want to expose a mechanism where the user can select a cell value for copy/paste to clipboard. Is there a way to do this? For example, double clicking a cell copies the cell value where as single click always selects the row. Or right click on cell exposes the option to "Copy cell" value?

Thanks!

GridView

asked on 18 May 2012

1 answer

85 views

Gridview and SqlCeResultSet

Does the wpf GridView support direct binding to SqlCeResultSet?

GridView

answered on 18 May 2012

1 answer

244 views

Overlay Icon

Hi,

I'm using RadControls for WPF (version 2012.1.326.40), and my question is about the RadTreeView.
Is it possible to show an overlay image over the RadTreeViewItem's DefaultImageSrc ?

Best regards,

TreeView

answered on 18 May 2012

3 answers

340 views

Trouble putting ContextMenu on ListBoxItems nested in RadPanelBarItem

Hi All,

Edit: The title should state that the issue is with ListView items and not ListBox items. Cannot change it now - sorry about the confusion.

I am trying to put a context menu on items in a ListView when that ListView is contained within a RadPanelBarItem that has a context menu. I hope the code example below illustrates what I am trying to do. If I don't add the following then the list items show the expected menu.

<telerik:RadContextMenu.ContextMenu>

<telerik:RadContextMenu x:Name="_macroActionContextMenu" />

</telerik:RadContextMenu.ContextMenu>

When I add it (as shown in the snippet below) then I always get the context menu associated with the RadPanelBarItem when I right click on the ListView elements rather than the context menu specified for the ListView.ItemContainerStyle.

Any help would be appreciated. My code snippet is below.

<telerik:RadPanelBarItem Name="_rpbiMacros" Header="Macros" IsDropAllowed="False" Foreground="#FF4D4D4D" BorderBrush="#FFBCB596" >

<telerik:RadContextMenu.ContextMenu>

<telerik:RadContextMenu x:Name="_macroActionContextMenu" />

</telerik:RadContextMenu.ContextMenu>

<Grid Width=

"{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type telerik:RadPanelBar}}, Path=ActualWidth, Converter={StaticResource mathConverter}, ConverterParameter=@VALUE-12;0}"

>

<WrapPanel Name="_wrpMacroActions"

Visibility=

"{Binding ViewMacroActionListAsIcons, Converter={StaticResource boolToVisibilityConverter}, ConverterParameter=Visibility.Collapsed}"

>

<ItemsControl ItemsSource="{Binding MacroActionViewModelList}" >

... omitted for clarity

</ItemsControl>

</WrapPanel>

<ListView x:Name="_lviewMacroActions" ItemsSource="{Binding MacroActionViewModelList}" ButtonBase.Click="OnClick_ListViewHeader"

Visibility=

"{Binding ViewMacroActionListAsIcons, Converter={StaticResource invertBoolToVisibilityConverter}, ConverterParameter=Visibility.Collapsed}"

>

<ListView.Resources>

<ContextMenu x:Key="itemContextMenu">

<MenuItem Header="Open" Click="OnClick_EditMacroAction">

</MenuItem>

<MenuItem Header="Delete" Click="OnClick_DeleteMacroAction" >

<MenuItem.Icon>

<ContentControl Template="{StaticResource _rscDeleteImage}" />

</MenuItem.Icon>

</MenuItem>

</ContextMenu>

</ListView.Resources>

<ListView.ItemContainerStyle>

<Style TargetType="{x:Type ListViewItem}">

<Setter Property="telerik:RadContextMenu.ContextMenu" Value="{StaticResource itemContextMenu}" />

<EventSetter Event="MouseDoubleClick" Handler="OnDoubleClick_MacroAction" />

</Style>

</ListView.ItemContainerStyle>

<ListView.View>

<GridView>

<GridViewColumn Header="Name" DisplayMemberBinding="{Binding Model.MacroName}"/>

<GridViewColumn Header="Description" DisplayMemberBinding="{Binding Model.MacroDescription}" />

</GridView>

</ListView.View>

</ListView>

</Grid>

</telerik:RadPanelBarItem>

x

ContextMenu

answered on 17 May 2012

1 answer

154 views

Drag & Drop between two ListBoxes... DropInfo

HI,

i'm using RadControls for WPF Q1 2012 SP1 + c# to create my application. The problem i have:

I use two listboxes wich are bind to an observableCollection. Now i want to drag an item from listbox A to listbox B
what is quiet simple. But on Drop in listbox B i want to save changes in my database. how do i get the information
isdropped, which item is dropped,...?

I tried the Drop (drop="myDropEvent") Event from the listbox, but that was not helpfull.

Thanks
regards
Rene

DragAndDrop

answered on 17 May 2012

3 answers

127 views

Displaying three columns in one column

Hello,

I am trying to display 3 columns in one.
The result must be like this http://imageshack.us/photo/my-images/560/headergbiv.png/
Because the number of columns to display is variable the TreeListView is completly created in C#.
Is it possible to create such headers in this case?

Thank you

TreeListView

answered on 17 May 2012

1 answer

137 views

SnapBehavior for Resources

I know how to implement a SnapBehavior for a ViewDefinition. But is there a way to implement different SnapBehaviors for different resources in the same view?

ScheduleView

answered on 17 May 2012

3 answers

222 views

Asynchrounous loading of tile view- best practice suggestions please

I am using the radTileview that has lots of child controls in each tileitem . The itemsource of the tileview can be potentially very large ( in millions). If I try to load all the tiles, the ui hangs and it takes too long. So what I want to do is read the first 10 data items for the first 10 tileitems from my datasource and show it on the screen and then in the background keep populating the datasource model ( which is an observable collection ). As the datasource gets populated, the tileview should refresh and show the new items.
I tried the following
1. Creating the data source on a background thread, but this does not refresh the ui
2. Using the dispatcherTimer, but the behaviour is quite random. It refreshes the first lot of data and then the screen blanks out

I have set the following properties on the tileview

IsAutoScrollingEnabled

="True" IsVirtualizing="True"

Please can you suggest some best practises and I would be very obliged if you can send me some sample / example code. The tile view

Many thanks,
Subarna

TileView

answered on 17 May 2012